/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.lgwen.spark.ml.learning;

import org.apache.spark.sql.SparkSession;

// $example on$
import java.util.Arrays;
import java.util.List;

import org.apache.spark.ml.feature.StringIndexer;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.RowFactory;
import org.apache.spark.sql.types.StructField;
import org.apache.spark.sql.types.StructType;

import static org.apache.spark.sql.types.DataTypes.*;
// $example off$

public class JavaStringIndexerExample {
    public static void main(String[] args) {
        SparkSession spark = SparkSession
                .builder().master("local[*]")
                .appName("JavaStringIndexerExample")
                .getOrCreate();

        // $example on$
        List<Row> data = Arrays.asList(
                RowFactory.create(0, "a"),
                RowFactory.create(1, "b"),
                RowFactory.create(2, "c"),
                RowFactory.create(3, "a"),
                RowFactory.create(4, "a"),
                RowFactory.create(5, "c"),
                RowFactory.create(5, "eass"),
                RowFactory.create(5, "d"),
                RowFactory.create(5, "cfff")
        );
        StructType schema = new StructType(new StructField[]{
                createStructField("id", IntegerType, false),
                createStructField("category", StringType, false)
        });
        Dataset<Row> df = spark.createDataFrame(data, schema);

        StringIndexer indexer = new StringIndexer()
                .setInputCol("category")
                .setOutputCol("categoryIndex");

        Dataset<Row> indexed = indexer.fit(df).transform(df);
        indexed.show();
        // $example off$

        spark.stop();
    }
}
